The present disclosure is directed to an apparatus which is used with devices creating turbulence in a pipeline. This apparatus reduces the downstream turbulence. In context, this refers to the fluid flow turbulence that might arise downstream of a ball valve in a natural gas pipeline. Consider a pipeline of a nominal 12 inch rating having a 12 inch ball valve supported on valve mounting trunnions. A valve operator is a mechanical device used to open and close the valve element. It is opened or closed by rotating the valve element so that the passage is at right angles to the axis of the pipeline, thereby closing the pipeline to fluid flow. On opening, rotation aligns the valve element passage. When the valve element is fully opened or fully closed, turbulence is not a problem. There is, however, a problem of turbulence on the transition between the fully opened or fully closed position. For instance, when the valve element is only opened slightly, there is a tremendous amount of turbulence created. This derives from the fact that the valve bore, rather than being fully opened, is very substantially closed except for a small quarter moon region at one side or the other depending on the rotation of the valve element and the extent of its opening. This is true of a ball valve and is also true of other types of valve mechanisms. There are gate valves, namely those devices which utilize a transverse gate guided in a set of tracks. The gate element may even be tapered to enable it to fit snugly in the tracks. Even in this instance, there typically will be a small crack or opening when the gate element is not seated fully. In other words, there is again a small region where fluid flow is permitted as the gate is moved toward the fully opened or fully closed position. There are other valves which have similar problems. Suffice it to say, at the partially opened state, turbulence is created downstream of a valve during transition between the fully opened and the fully closed positions. Further, a ball valve (for example) stays in the restricted position when used for modulating the flow.
One situation involving a valve creating downstream turbulence relates to a modulating valve. When a large supply line at very high pressure terminates at the edge of a city, the large, high pressure line connects at a sales station to one or more local distribution lines. A city of 400,000 people with typical industrial plants may have as many as 1000 modulating devices at various locations around the city. They typically are valves used to modulate or regulate the flow so that the local distribution lines (of smaller diameter) are provided with gas at a lower pressure for home, office and plant customers. In fact, the modulating valves will be left in a highly turbulent position for indefinitely long intervals. This creates turbulence without ceasing.
The valves just mentioned are merely exemplary of the problem. The problem derives primarily from the intermediate position of the moveable element which cooperates with the valve seat to plug fluid flow through the line. Suffice it to say, the entire flow pattern is impacted downstream of the valve. The turbulence can extent downstream as much as 20-100 diameters in length, referring to the diameter or nominal size of the pipeline. The turbulence downstream creates many difficulties. For one, it creates a tremendous amount of noise or vibration, or both. The noise and vibration tends to wear out the equipment in the near vicinity. Moreover, the turbulence created by the partially opened valve element fatigues the metal of the pipe, supporting structure for the valve, valve operators and the like. Valves of this sort are normally associated with other equipment. It is not uncommon to require several such valves at a pump station or product sales station. The pump station may involve millions of dollars of high pressure compressors and the like to boost the pressure to assure that the gas flow continues along the pipeline. Moreover, the vibrations do substantial harm to the adjacent buildings and structures. A typical pump station including a multi-horsepower power plant and turbine pump will normally be associated with several valves of this sort. This set of equipment is quite expensive to erect and maintain. If the valves create turbulence in the form of noise and vibration, it is expensive to deal with both the noise and the vibration in the immediate vicinity. This require substantial damping and other vibration suppression techniques.
An important feature of the present disclosure is the provision of a system which enables downstream reduction of noise and vibration. It is a device best installed serially in a pipeline on the downstream side of a valve, such as ball valves, gate valves and the like. Particularly in a high flow, high capacity line, the vibration can create difficulties for great distances downstream. This apparatus enables the reduction of noise immediately downstream. Moreover, it involves a structure which is installed at the downstream location so that maldistribution of fluid flow downstream of the partially opened or partially closed valve is remedied. It is a structure of which has a sufficient length to enable a nest of internal tubes to redistribute the fluid flow across the cross sectional area of the pipeline. A nest of parallel tubes is utilized. Their inputs are downstream of the turbulence creating valve. The tubes collectively have a cross sectional area which is approximately equal to or greater than the cross sectional area of the pipeline. The tubes are arranged so that the open ends of the tubes begin just downstream from the turbulence creating valve. With a distribution which can be described as mixed, the tubes are permitted between their open end inputs and theri outputs to redistribute the flow. For instance, the tubes collect the flow of turbulent fluid in a number of inlet passages, and redistribute that flow across the cross sectional area. The tubes are held in a housing. The housing has an enlarged, bell shaped central portion which is bigger in diameter than the nominal size of the pipeline. It is bigger to permit the tubes collectively to fit in serpentine fashion amongst other tubes to achieve flow distribution across the pipeline. The tubes are free of sharp bends or other obstructions in the tubes that might otherwise tend to create tube induced turbulence. They provide a streamline flow at the outlet ends. Thus, where the cross sectional area of the pipeline is divided into a number of tubes (represented by the number N, which is a whole number integer), the rearrangement of flows yields a smooth downstream flow which is substantially free of turbulence. A method is also set forth wich involves the arrangement of multiple tubes to redistribute the fluid flow and thereby reduce turbulence in the system.